Device for adjusting the position of at least one movable part of a vehicle seat

ABSTRACT

A device for adjusting the position of at least one movable part ( 2 ) of a vehicle seat ( 1 ), of the type comprising two connection elements ( 4, 5 ), at least one ( 4 ) of said two elements being secured to said movable part ( 2 ) of the seat, means ( 6 ) for connecting the two elements ( 4, 5 ) together such as to enable at least the element ( 4 ) connected to the movable part ( 2 ) to rotate about a first axis (A 1 ), and control means ( 7 ) by which said element ( 4 ) connected to the movable part ( 2 ) of the seat is enabled to rotate or, alternatively, be locked in a preferred angular position; in which the control means ( 7 ) comprise an at least partly circular toothing ( 9 ) provided on said element ( 4 ) connected to the movable part ( 2 ) of the seat, at least two gears ( 10 A, B) engaging with said toothing ( 9 ) and movable with planetary motion about said first axis of rotation (A 1 ), and a lever system ( 17, 18 ) arranged to shift said gears ( 10 A, B) into a first position (B) in which said gears engage with each other and with said toothing ( 9 ), so preventing rotation of said element ( 4 ) connected to the movable part ( 2 ) of the seat, and into a second position (R) in which the gears ( 10 A, B) engage only with said toothing ( 9 ), so enabling rotation of said element ( 4 ) connected to the movable part of the seat, said lever system ( 17, 18 ), gears ( 10 A, B) and toothing ( 9 ) maintaining the gears ( 10 A, B) always in mutually complementary positions such as to always enable the gears to engage with each other when the gears pass from said first to said second position.

[0001] The present invention relates to a device for adjusting the position of at least one movable part of a vehicle seat, in particular the position of its seat back relative to its seat cushion, in accordance with the precharacterising part of the main claim.

[0002] Known devices for adjusting the position of the seat back relative to the seat cushion, if using gears with planetary motion (see for example U.S. Pat. No. 5,704,870 or U.S. Pat. No. 4,211,1451 or EP0332340), generally comprise a large number of components of difficult and complicated construction and assembly, which largely influence the final device production costs.

[0003] It also often happens that, with use, radial slack arises between the components of known devices, causing a decline in the quality and accuracy of the seat adjustment, and in the long term leading to a deterioration in the device itself.

[0004] An object of the present invention is to provide a device for adjusting the position of at least one movable part of a vehicle seat, in particular the position of its seat back relative to its seat cushion, which comprises a small number of components of simple construction and rapid assembly, and ensures an absence of radial slack between its components.

[0005] This and further objects which will be apparent to an expert of the art are attained by a device in accordance with the characterising part of the main claim.

[0006] The present invention will be more apparent from the accompanying drawings, which are provided by way of non-limiting example and in which:

[0007]FIGS. 1 and 2 are a front schematic view of a device according to the invention in two different operating positions,

[0008]FIGS. 3 and 4 are front schematic views thereof, which are taken in the same manner as FIGS. 1 and 2, but in which a component of the device is omitted in order to show the positioning of the gears in the two different operating positions,

[0009]FIGS. 5A, 5B, 5C are schematic sections taken on the lines 5A/5A, 5B/5B, 5C/5C of FIG. 3,

[0010]FIGS. 6-10 are front schematic views of some of the components of the device,

[0011]FIGS. 11A, 11B, 11C, 11D, 11E are side schematic views of a seat comprising a device of the invention associated with the seat in the form of different variants and in different positions of utilization.

[0012] With reference to said figures, the device of the invention is arranged to adjust the position of two movable parts of a vehicle seat 1 (FIG. 11A), in particular the device being arranged to adjust the inclination of the seat back 2 to the seat cushion 3. The device comprises: two plate elements 4, 5, positioned one in front of the other and secured to the support frames 3A, 2A of the seat cushion 3 and seat back 2, means 6 for connecting the two elements 4, 5 together such as to enable one of said elements to rotate relative to the other about a first axis A1 (FIG. 5A), and control means 7 by which said element 4 is enabled to rotate or, alternatively, be locked in a preferred position. More specifically, the two plate elements 4 and 5, shown in FIGS. 6 and 7, are both of the same shape in the illustrated example and comprise a circular part 4A, 5A from which there extends an arm 4B, 5B to be rigidly fixed, in conventional manner, to the frames of the relative device support structures. The plate element 5 is that to be fixed to the frame 3B of the cushion 3 of the seat and, in the embodiment of FIG. 11A, is unable to rotate but only translate together with the seat. This fixed element 5 presents two slots 7A, 7B disposed spaced apart along the same circumference C concentric with the centre of rotation A of the two plate elements, and three through holes 8A, B, C. The other plate element 4 is that to be fixed to the frame 3A of the seat back in the embodiment shown in FIG. 11A. When released from the seat, this element 4 can rotate through 3600 about the other plate element, on an axis of rotation A1 (FIG. 5A) perpendicular to the plate elements and concentric with the circular parts 4A, 5A of these elements. The element 4 presents in its circular part 4A a circular aperture having along its edge a circular toothing 9 concentric with the centre of rotation A of the two plate elements and with the axis of rotation A1 of the element 4. In the circular toothing there engage two gear wheels 10A, 10B arranged to move with planetary motion, i.e. each with a rotary movement about its axis A2, A3 (FIG. 5) and a simultaneous rotary movement about the axis A1 which passes through the centre A of the circular aperture 9 and represents the axis of rotation of the fixed other element 5. The two axes of rotation A2, A3 are parallel to and equidistant from the axis A1 and are hence also perpendicular to the elements 4, 5.

[0013] The gear wheels 10A, B and the toothing 9 are of substantially conventional type and shaped such as to enable the gear wheels 10A, B to engage with each other and with the toothing 9 (FIG. 3), to lock the two plate elements 4 and 5 together in a preferred position, or alternatively to engage with the toothing 9 but not with each other (FIG. 4), to enable the movable element 4 to rotate about the fixed element 5. The gear wheels 10A, B also always maintain a complementary position one to the other and to the toothing 9, so as to always be able to engage with each other when they pass from the position in which they are not in mutual contact to the position in which they are in mutual contact.

[0014] Advantageously, the gear wheels 10A, B have the same thickness as the movable element 4, so as to be housed within the element 4 with their base walls resting, respectively, against one face of the fixed plate element 5 and against one face of a discoidal retention element 12 or disc (FIG. 5B) maintained in position by an annular element 13 rigidly fixed, for example by welding, to the movable plate element 4 or formed in one piece with that element. The disc 12 has a greater diameter than the toothed aperture of the element 4 so that the disc 12 rests at least partly on the element 4. The disc element 12 presents two slots 13A, B and three through holes 14A, B, C, these being positioned and shaped identically to those 7A, B, 8A-C present in the plate element 5. The annular element 13 prevents radial slack in the disc 12 and maintains concentricity of the various device components. The disc 12 is rigidly fixed to the plate element 5 by three connection members 15A, B for example of the nut and bolt or rivet type, passing through the holes 8A-C of the plate element 5 and 14A-C of the disc 12, the first two members 15 (FIG. 5C) comprising a central portion T having the same thickness as the element 4 so as to axially secure the disc 12 to the fixed plate element 5 at a predetermined distance apart. The other member 14 also acts as a fulcrum for two levers 17, 18 described in detail hereinafter (FIG. 5A) by which the device is operated. It should be noted that the diameter of these pins is slightly less than that of the holes 8A-C so that they are housed with slight radial slack in these holes.

[0015] The movable plate element 4 is “hinged” to the plate element 5, in the sense that the movable element 4 can only rotate about the axis A1 (FIG. 5A) passing through the centre of the elements 4, 5, 12, 13, any axial movement of it being prevented by the connection between the disc 12 and the fixed element 5 and the fact that the disc 12 rests on the movable element 4, and any radial movement of it being prevented by the cooperation between the annular element 13 and the disc 12.

[0016] The gear wheels 10A, B are connected to the fixed disc 12 and to the fixed plate element 5 by connection members 15C, D (FIG. 5B) engaging in the slots 7A-B and 13A, B, such as to be free to rotate about the respective hinging axes A2, A3. The members 15C, D also act as rotation pins for the device operating levers 17, 18 and comprise portions T1, T2 arranged to space these levers from each other and from the fixed disc 12.

[0017] The control means 7, by which the plate element 4 is enabled to rotate or, alternatively, be locked in a preferred position, comprise a lever system for shifting the gear wheels 10A, B into a first position B for device locking (FIGS. 1 and 3), in which they engage with each other and with the circular toothing 9, or into a second position R for device adjustment, in which the gear wheels engage only with the circular toothing 9, and for returning the gear wheels from the adjustment position to the locked position by making their toothings engage when they are again brought into contact with each other. For this purpose, the control means 7 comprise the control lever 17 and the auxiliary lever 18, both pivoted on the pin 15B (FIG. 5A). The levers 17 and 18 both present a semicircular slot 21, 22 (FIGS. 9 and 10) for passage of the pivot pin 15B, a hole 23 for passage of the pins 15C, D (FIG. 5B) fixed to the gear wheels 10A, B, and a hole 19 for connecting the ends of the levers to an elastic member 20 (FIGS. 1 and 2), for example a spring, arranged to urge the ends 17A and 18A of the two levers 17, 18 towards each other. The two levers are also connected together by a pin 24 (FIG. 10) extending from the auxiliary lever 18 and arranged to engage in a slot 25 in the control lever 17. The two levers 17, 18 cannot move axially as they are retained by rivets or bolts (not shown) engaging the connection pins 15B, C, D, and can therefore only rotate about the pin 15B. However, as the pin 15B engages in the slots 21, 22 (FIGS. 9, 10) and the pins 15C, D engage in the slots 7A, B 13A, B of the element 5 and the element 12 respectively, on rotating the control lever 17 the two levers 17, 18 can also translate parallel to the plates 4 and 5 (as shown in FIGS. 1-4).

[0018] It should be noted that during operation of the lever system, the rotation pins of the gear wheels 10A, B always remain equidistant from the pivot pin 15B of the lever system.

[0019] The two slots 21 and 22 are shaped specular to each other about the longitudinal axis L (FIG. 1) of the fixed plate element 5. The levers 17 and 18, the slots 21 and 22, and those of the elements 5 and 12 are shaped such that when the lever system is in its rest position B (FIGS. 1 and 3) by the action of the spring 20, the lever arms carrying the gear wheels 10A, B urge these latter to engage with each other and with the internal toothing 9 of the movable plate element 4, to hence securely lock the movable element 4 to the element 5 and hence prevent rotation of said element 4. When in this position the gear wheels 10A, B, by the effect of the spring 20, are pressed against the circular toothing 9, to hence eliminate any possible slack between the movable plate element 4 and the fixed plate element 5 during rotation.

[0020] It should also be noted that the levers 17, 18 are shaped such that when in their rest position (FIGS. 1, 3), the spring 20 exerts on the pivot pins 15B (FIG. 5A) and on the pins 15C, D, A (FIGS. 5C, D) which connect the disc 12 to the plate 5 an action directed along the longitudinal axis L (FIG. 1) of the plate element 5 able to move these pins a few millimetres towards the movable element 4, and hence also move the disc 12 against the annular element 13 into the point indicated by C in FIG. 1. By virtue of the contact between the disc 12 and ring 13 (FIG. 1) the fixed plate element 5 is put under tension against the movable plate element 4, so eliminating any slack between said two elements. Consequently the lever system, when in its rest position or position in which it locks the movable plate 4, is able to securely fix together the plate 4 and the fixed plate 5, eliminating any possible slack between the two plates, by virtue of a double thrust action, exerted on the gear wheels 10A, B in a first direction D1 (FIG. 1), and on the combined gear wheels, guide plate 12 and movable plate 4 in a second direction D2, opposite the first. It should be noted that the pins 15A, B, C, D can be shifted by the lever system because they engage in holes in the plate 5 and disc 12 which are greater in size than the pins inserted into them. If instead the lever 17 is pushed downwards (direction D3 FIG. 1) the lever system 7 is put into the adjustment position, enabling the movable plate 4 to rotate. In this respect, on lowering the lever 17 this, together with the other lever 18, translates coaxially to the longitudinal axis of the fixed plate (in the direction D2 FIG. 1) to also drag during this movement the gear wheels 10A, B pivoted to the levers, to withdraw them one from the other so that they no longer obstruct each other but remain however in contact with the internal circular toothing 9 of the movable plate 4 along which they rotate during this movement. Hence on lowering the lever 17 the plate element 4 can be freely rotated into any angular position about the fixed element 5. During the rotation of the plate 4 the gear wheels 10A, B are rotated by the toothing 9. The translation of the levers 17, 18 and of the gear wheels 10A, B is guided and limited by the slots 7A, B and 13A, B provided in the fixed plate 5 and in the disc 12. It should be noted that the slots 7A, B 13A, B maintain the rotation axes A2, A3 of the gear wheels 10A, B equidistant from the central rotation axis A1 of the movable element 4 during the “release” movement of the gear wheels. This is ensured by the fact that the slots extend along a circular arc concentric to the toothing 9. Moreover, when the lever 17 is lowered, there is no longer exerted on the pivot pin 15B a thrust coaxial to the longitudinal axis L, hence a slight slack arises between the fixed plate 5 and movable plate 4. This slack is however not detrimental during this adjust stage of the inclination of the movable plate 4.

[0021] By virtue of the pin 24 (FIG. 10) of the auxiliary lever 18 and its engagement in the slot 25 of the control lever 17, movement is transmitted from the lever 17 to the lever 18 with symmetry about the longitudinal axis L of the plate element 5. The slot 25 enables take up of any slack between the gear wheels 10A, B when these are required to engage with each other and with the toothing 9. This simplifies the construction of the gear wheels of the device, which do not need to be constructed with excessive precision; proper operation of the device is therefore possible even if the toothings are not formed accurately. In the device of the invention the toothings in fact operate to provide a wedging action when locking the two elements 4 and 5 together, and to merely drag the gear wheels 10A, B during rotation of the element 4.

[0022] The device of the invention overcomes many of the drawbacks present in known devices. In this respect, using a very small number of components of simple construction and assembly, the device of the invention enables the movable element 4 to be adjusted continuously through an angle of 360° rather than stepwise relative to the fixed element 5, without any slack or any decline occurring in the position of the seat back relative to the seat cushion once the two elements 4 and 5 have been locked together. Moreover, as the device of the invention does not involve rotating the plate 4 in steps, it operates perfectly even for very small movements.

[0023] FIGS. 11A-E show some possible ways of using the device. In FIG. 11A the device is used only for adjusting the inclination of the seat back 2, reference having been made to this application in the aforegoing description. FIGS. 11B, C show the use of a first device of the invention (indicated by P1) for adjusting the inclination of the seat back 2 as in the preceding application, and of a second device of the invention (indicated by P2) for raising the seat cushion. In this latter application the movable plate 4 of the device P2 is secured to that end of the frame 3A of the seat cushion 3 hinged to the seat back by the device P1, whereas the fixed part of the device P2 is secured to the usual slidable frame 3B which enables the seat to slide horizontally. The other end of the frame 3A of the seat cushion is hinged to a support 3C also rigidly secured to the horizontally slidable frame 3B of the seat. With the device P2, by acting on the operating lever 17 the seat cushion can either be locked in a desired position or its position varied by rotating the rear part of the seat cushion about its front part (as shown in FIGS. 11B, C). The device P2 is advantageously provided on the opposite side of the seat to that on which the device P1 is positioned.

[0024]FIGS. 11D, E show an arrangement in which two devices P1, P2 of the invention are again provided; in a first device P1 the movable element 4 is again secured to the frame 2A of the seat back as usual, whereas the fixed element 5 is secured to a plate 2B rigidly fixed to the frame 3B for the horizontal sliding of the seat and not to the seat cushion. This latter is free from the seat back and is connected at its front to the frame 3B for the horizontal sliding of the seat by a support 3C to which it is hinged, and at its rear by the second device P2, the movable part 4 of which is secured to the frame 3A of the seat cushion, whereas its fixed part 5 is secured to the seat frame 3B. In this application of the device it is hence used both to adjust the inclination of the seat back 2 and to adjust the inclination of the seat cushion 3 (as shown in FIGS. 11D, E which show two different positions of the seat cushion).

[0025] The device of the invention could also be used by utilizing the rotation of both the plate elements 4 and 5, for example by hinging at least one of the ends of these elements to a block slidable horizontally along a guide, while maintaining the other end fixed and connecting the movable part of the seat to a pin, for example passing through a hole 30 (FIG. 3). With this further variant the device can be used, for example, to vary the height of a part of the seat cushion secured to the pin passing through the hole 30. In this variant, both the connection elements 4 and 5 rotate and translate horizontally. As the device enables the movable element 4 to be rapidly and stably moved angularly through 360°, it is particularly suitable for all those applications which require the seat back to undergo a “table” or “bed” movement.

[0026] Finally, it should be noted that the aforedescribed embodiment has been provided by way of example only, and that numerous variants are possible all falling within the same inventive concept, for example the lever system 7 could be of type different from that illustrated provided it is able to lock the gear wheels 10A, B together and to the toothing 9 while at the same time putting the plates 4 and 5 under mutual tension to hence eliminate slack between said plates, or alternatively to enable the plate 4 to rotate and the lever system, once released, to return to its locking position.

[0027] For example the lever system could employ a “scissor” action which would require only the prolongation of the end 18B (FIG. 10) of the auxiliary lever 18.

[0028] Again, the gear wheels 10A, B could consist of toothed circular sectors if desired to limit the rotation of the plate 4. Likewise, the circular toothing 9 could extend only through an arc of a circle. Hence in the present context semicircular toothings and wheels are also included within the concept of circular toothing and gear wheels.

[0029] In a manner totally obvious to the expert of the art, the number of gear wheels 10A, B could also be increased, for example to four. The shape of the parts 4B and 5B (FIGS. 6 and 7) could also be different from that shown, in order to make these parts more easily fixable to the seat support structures. 

1. A device for adjusting the position of at least one movable part (2) of a vehicle seat (1), of the type comprising two connection elements (4, 5), at least one (4) of said two elements being secured to said movable part (2) of the seat, means (6) for connecting the two elements (4, 5) together such as to enable at least the element (4) connected to the movable part (2) to rotate about a first axis (A1), and control means (7) by which said element (4) connected to the movable part (2) of the seat is enabled to rotate or, alternatively, be locked in a preferred angular position; characterised in that the control means (7) comprise an at least partly circular toothing (9) provided on said element (4) connected to the movable part (2) of the seat, at least two gears (10A, B) engaging with said toothing (9) and movable with planetary motion about said first axis of rotation (A1), and a lever system (17, 18) arranged to shift said gears (10A, B) into a first position (B) in which said gears engage with each other and with said toothing (9), so preventing rotation of said element (4) connected to the movable part (2) of the seat, and into a second position (R) in which the gears (10A, B) engage only with said toothing (9), so enabling rotation of said element (4) connected to the movable part of the seat, said lever system (17, 18), gears (10A, B) and toothing (9) maintaining the gears (10A, B) always in mutually complementary positions such as to always enable the gears to engage with each other when the gears pass from said first to said second position.
 2. A device as claimed in claim 1, characterised in that the lever system (17, 18) comprises at least one elastic member (20) and means (15A-D, 12, 13) for connecting the levers together and to the connection elements (4, 5) such as to put the gears (10A, B) under tension between themselves and with the toothing (9), and to put said two connection elements (4, 5) under tension, when the gears are in the first position (FIG. 3), to hence eliminate slack between the two connection elements (4, 5).
 3. A device as claimed in claim 1, characterised in that the two connection elements (4, 5) are substantially plate-like, are positioned in two mutually parallel planes and comprise two circular parts (4A, 5A) which are coaxial with each other and with the axis of rotation (A1) of the connection element (4) connected to the movable part (2) of the seat.
 4. A device as claimed in claim 1, characterised in that the element (4) connected to the movable part (2) of the seat presents an at least partly circular aperture, in the edge of which there is provided an at least partly circular toothing (9) concentric with the axis of rotation (A1) of said element (4).
 5. A device as claimed in claim 4, characterised in that the gears (10A, B) have the same thickness as the element (4) presenting the circular toothing (9).
 6. A device as claimed in claim 1, characterised in that the gears are gear wheels (10A, B).
 7. A device as claimed in claim 5, characterised in that the gears (10A, B) are retained axially on one side by a portion of one of the faces of that connection element (5) not secured to the movable part (2) of the seat, and on the other side by a discoidal element (12) rigidly secured axially to said connection element (5).
 8. A device as claimed in claim 7, characterised in that that connection element (4) secured to the movable part (2) of the seat presents an annular element (13) for radially retaining the discoidal element (12).
 9. A device as claimed in claim 1, characterised in that the means (6) which enable that element (4) connected to the movable part (2) of the seat to rotate comprise a discoidal element (12) secured axially to the other connection element (5) in such a manner that the element (4) connected to the movable part of the seat is in contact with a portion of one face of said discoidal element (12) and with a portion of one face of said other connection element (5), the discoidal element (12) being housed in a seat provided in a retention element (13) of element (4) connected to the movable part of the seat, which prevents radial movement of said discoidal element.
 10. A device as claimed in claim 1, characterised in that the lever system comprises a first control lever (17) and at least one auxiliary lever (18), said levers presenting a common pivot pin (15B).
 11. A device as claimed in claim 10, characterised in that the pivot pin (15B) engages in a semicircular aperture (21, 22) provided in each of said levers and shaped such as to enable the levers, during their rotation about said pin (15B), to also undergo simultaneous translation along a direction (L) parallel to the planes in which the connection elements (4, 5) lie.
 12. A device as claimed in claim 11, characterised in that the semicircular apertures (21, 22) are shaped such as to at least partially shift the pivot pin (15B) when the lever system shifts the gears into the first position (B) which prevents rotation of that element (4) connected to the movable part of the seat, said shift putting the two connection elements (4, 5) under tension and locking them rigidly together.
 13. A device as claimed in claim 1, characterised in that the gears (10A, B) present rotation pins (15C, 15D) engaging in semicircular apertures (7A, B; 13A, B) extending along circumferences which have the same diameter and are concentric with the axis of rotation (A1) of the element (4) connected to the movable part (2) of the seat (1) and with the lever system (17, 18).
 14. A device as claimed in claim 13, characterised in that the rotation pins of the gears (10A, B) are always equidistant from the pivot pin (15B) of the lever system.
 15. A device as claimed in claim 1, characterised in that that connection element (4) connected to the movable part of the seat is connected to a frame (2A) of the back (2) of the seat (1), the other connection element (5) being connected to a frame (3A) of the cushion (3) of the seat.
 16. A device as claimed in claim 1, characterised in that that connection element (4) connected to the movable part of the seat is connected to a frame (3A) of the cushion (3) of the seat (1), the other connection element (5) being connected to a lower frame (3B) of the cushion (3) of the seat, said seat cushion being hinged at its front.
 17. A device as claimed in claim 1, characterised in that that connection element (4) connected to the movable part of the seat is connected to a frame (2A) of the back (2) of the seat (1), the other connection element (5) being connected to a frame (2B) secured to a lower frame (3B) of the seat.
 18. A device as claimed in claim 1, characterised in that that connection element (4) connected to the movable part of the seat is connected to a frame (3A) of the cushion (3) of the seat (1), the other connection element (5) being connected to a lower frame (3B) of the seat, said seat cushion being hinged at its front.
 19. A device for adjusting the position of at least one movable part (2) of a vehicle seat (1), of the type comprising means (6) for connecting two support and connection elements (4, 5) together such as to enable said two elements (4, 5) to rotate about a first axis (A1), and control means (7) by which said elements (4) connected to the movable part (2) of the seat are enabled to rotate or, alternatively, be locked in a preferred angular position; characterised in that the control means (7) comprise an at least partly circular toothing (9) provided on one of said elements (4), at least two gears (10A, B) engaging with said toothing (9) and movable with planetary motion about said first axis of rotation (A1), and a lever system (17, 18) arranged to shift said gears (10A, B) into a first position (FIG. 3) in which said gears engage with each other and with said toothing (9), so preventing rotation of said elements (4), and into a second position (FIG. 4) in which the gears (10A, B) engage only with said toothing (9), so enabling rotation of said elements (4), said lever system (17, 18), gears (10A, B) and toothing (9) maintaining the gears (10A, B) always in mutually complementary positions such as to always enable the gears to engage with each other when the gears pass from said first to said second position.
 20. A device as claimed in claim 19, characterised by presenting the characteristics defined in the characterising part of one or more of claims from 2 to
 19. 21. A vehicle seat, characterised by comprising at least one device in accordance with claims from 1 to
 20. 